some isps block ident requests, altho i have no idea if comcast is one of them. you can call and ask them (assuming they will give you a straight answer) or check on
www.practicallynetworked.com or
http://www.dslreports.com/forums/all to see what info they have on comcast.
whether you use DALnet or not, they have some good info about ident probs at
http://kline.dal.net/exploits/ident.htm and the links there. the link to windows ident also has links to standalone ident software if needed
